1. Field of the Invention
The present invention relates to a drive disk for the tool of a machine for the repair and/or maintenance of floors.
2. Description of Prior Art
Machines for the repair and/or maintenance of floors, including a motor capable of rotationally driving at least one rotary tool through the use of a drive shaft at least substantially orthogonal to said tool are already known, especially from Patents GB-A-1,083,775 and U.S. Pat. No. 3,464,075, said tool being connected to said drive shaft by a drive disk which, close to its external periphery, is connected to the tool and, close to its center, is connected to the drive shaft, and allowing a relative inclination of limited amplitude of the axis of rotation of the tool with respect to said drive shaft. However, in these known machines, said disk is produced from an elastic material (metal or rubber) so that the degree of freedom of the tool parallel to the axis of the tool is limited by the elasticity of the disk and so that this results in the tool not being exactly coplanar with the floor. As a consequence, the surface being treated is attacked unevenly by said tool so that it cannot be perfectly uniform.
In order to overcome these drawbacks, the document EP-A-0,388,273 describes such a drive disk including a circular diaphragm made of an inelastic material which is supple perpendicular to its plane but which is rigid in its plane.
For example, said diaphragm consists of a web of synthetic material which is rigid in terms of torsional shear. Such a web may, for example, be of the type of those used for producing conveyor belts. It may consist of crossed fabrics made of polyester fibers coated with polyvinyl chloride.
Thus, since the material of said diaphragm is rigid in its plane, the disk can transmit the torque from the drive shaft to said tool, so that the latter is rotationally driven. Moreover, since the material of the diaphragm is supple perpendicular to its plane, such a disk makes it possible, particularly upon start-up, to "uncouple" the tool from the rest of the machine, making it easier to start the tool and to keep the latter perfectly parallel to the floor to be treated, during treatment. In addition, this disk allows the distribution of loads or of forces over the tool, which allows a lateral displacement of the machine.
In use, it has been observed that when such a disk was mounted on a machine imparting to said disk, and therefore to the rotary tool, a high nominal rotational speed, for example of the order of 1000 rpm, the operation of the disk was perfect, without side effects. In contrast, when the disk was mounted on a machine imparting a low nominal speed to it, for example 400 rpm, vibration appeared which was unpleasant for the operator using said machine, even though the latter was doing a good job.